Waveform diversity for ultra-wide band surveillance radars

The radio frequency spectrum has become very crowded with the increased use of commercial and personal communications devices. The worldwide spectrum committees require extreme measures to insure frequency avoidance by radar systems, to insure communications are maintained for emergency systems and flight safety. Radars operating in the frequency bands below 2 GHz have limited spectrum allocation, and are asking for more bandwidth for detection and localisation of earth resource and military uses. Hence, the radar community needs to adopt the techniques from cognitive radars to continue to provide the needed detection and characterisation of objects under concealing cover. This survey study attempts to provide an assessment for future research.